전기적으로 빠른 과도현상/버스트 복사 잡음에 관한 대책 연구

Abstract

Civilization using electromagnetic wave has a lot of advantages which is completely changing the life pattern of the mankind. However, Malfunction by various interference between electric equipments and hazards on health have become serious problems. Thus, Regulation of electromagnetic waves have been increasingly tighten up in most of the world, including Republic of Korea.

Most of the major countries have administered certified international laboratory under the ILAC in order to solve problems such as trade barriers from electric equipment which is not satisfied regulation of electromagnetic waves.

In Korea, KOLAS has made mutual recognition arrangements with the ILAC and laboratories accredited KOLAS have improved the reliability and repeatability of measurement through an accurate analysis of international standards.

In this dissertation, problems about EFT/Burst test, referenced in the IEC-61000-4-4 of the international standard related to verifying EMC of electric equipments, was analyzed and measuring reliability was studied. As a result, the improved EFT/Burst immunity test method which considering the radiated EFT/Burst signals has been proposed.

Firstly, the test sample was set up by the standard regulation and then the +4 kV EFT/Burst signal was generated by 1 m long power cable for 1 minute. Consequently, it was found that not only induced EFT/Burst signal along power line of EUT, but also directly radiated emission signal from the EFT/Burst signal generator.

The radiated emission signals was 30dB higher than limit of CISPR 22 which is international EMC standard. Moreover, the electric field strengths were measured by changing the distance from the point with the maximum radiated emission to the electric field strength tester. As a result, this electric field strength was 23 V/m which is higher than international EMC standard test level (CISPR 24). Therefore, it was confirmed that the probability of malfunction may be high when radiated emission of EFT/Burst noise exists near the EUT.

Then, reliability of measurement results of IEC61000-4-4 standard was discussed through the field strength measurement according to the separated distances of the receiver to the maximum source of the radiated EFT/Burst signals, the analysis of the influence from the power line type and length, the analysis depends on the type of the test sample, and the studies of suppression effect from the radiated EFT/Burst signals.

Consequently, the radiated EFT/Burst signals directly cause malfunction of EUT, and it was confirmed that malfunctions of EUT can be solved by applying countermeasure method of radiated noise. In addition, it was proposed that countermeasure method from EFT/Burst signals should be considered not only for conductive noise but also for the radiated noise.

Furthermore, reliable arrangement of EFT/Burst immunity test were searched according to the structure of the EUT’s enclosure, materials, and operating environment. In this dissertation, the improved EFT/Burst immunity test method which considering the radiated EFT/Burst signals has been proposed.